1. Field of the Invention
The present invention relates to the field of dough manufacture. More particularly, the invention is concerned with assessing flour samples for dough forming potential, monitoring subsequent dough formation and modifying the physical properties of the dough during the course of dough mixing. In practice, the levels of tyrosine, dityrosine and other tyrosine bonded compounds are measured in flour to predict dough forming properties, based on the potential level of tyrosine bonds that may be produced during mixing of the flour with water to produce a dough. The actual levels of bonds incorporating tyrosine formed in dough during mixing may also be monitored and manipulated as needed by the addition of oxidizing/reducing agents or tyrosine analogues to consistently produce high quality doughs.
2. Description of the Prior Art
In flour dough manufacture, dough is produced by mixing wheat flour and water. Other ingredients (e.g. salt) are added depending on the product being made. Dough made from wheat flour has a viscoelastic property not exhibited by doughs made from other cereals. This viscoelastic property is believed to be derived from gluten protein. The glutenin subunits, one of the two classes of storage proteins which are part of the gluten complex in wheat, are known to directly affect dough formation and bread making quality. Present theories regarding dough formation were developed with the idea that only disulfide crosslinks are involved in the mechanism of gluten structure formation. It was believed that these disulfide bonds were formed and/or broken and reformed during the mixing process and were ultimately responsible for the characteristics exhibited by a particular sample of dough.
Based on the intended use of the dough, different properties may be desired, i.e., a dough intended to be used for bread may have different desirable properties than a dough made for breakfast cereal processing. Additionally, similar flours used in dough processing may exhibit different characteristics during mixing due to environmental conditions present when the grain used to make the flour was growing or genetic differences. As can be seen, dough manufacture is affected by many different variables and it was heretofore impossible to predict with reasonable accuracy the qualities that any dough will exhibit during mixing based on an a priori analysis of the flour or wheat used.
The addition of oxidizing/reducing agents, metal chelating agents, or adjusting the dough pH during processing can affect the properties and consistency of the dough as desired. For example, a common modifier and improver of doughs, potassium bromate, has been determined to be potentially carcinogenic at certain levels and its use in bread doughs has been banned in the United Kingdom, Japan and New Zealand. The United States has limited the use of potassium bromate with maximum permitted levels of 50 or 75 ppm. However, following a request from the FDA in 1991, a majority of baking companies have voluntarily stopped using potassium bromate.
As a result of processing, dough can become sticky and reduce operating efficiency causing expensive delays and product loss. Alternatively, the dough can be overdeveloped or overworked resulting in low quality products. There is a point in time during mixing of every dough where continued mixing beyond that point results in a dough of inferior quality. Stopping the mixing process prior to that point also results in unacceptable dough quality. What is needed are methods of assessing dough forming potential of a flour prior to processing in order to precalibrate processing equipment thereby reducing the amount of manipulation required to efficiently produce an optimum dough; monitoring dough formation during processing so as to assess dough characteristics in a way that consistently results in product optimization; and manipulating dough formation during processing to effect optimization of the final dough product.